The first highly enantioselective conjugate addition of 2-acetyl azaarenes to α-substituted-β-nitroacrylates was successfully realized under mild conditions by a Ni(II)-bisoxazoline complex, providing the desired adducts bearing an all-carbon quaternary stereocenter in high yield with excellent enantioselectivity. The products obtained in this system could be readily converted into optically active β2,2-amino esters, succinates, lactones, and lactams.

A practical method of four-step synthesis towards novel (E)-5-(methoxyimino)-3,5-dihydrobenzo[e][1,2]oxazepin-4(1H)-one antifungals is presented, where a commercially available pesticide and pharmacology intermediate, (E)-methyl 2-(2-(bromomethyl)phenyl)-2-(methoxyimino)acetate (1), was used as starting material. These compounds were confirmed by 1H NMR, 13C NMR, high-resolution mass spectroscopy and X-ray crystal structure. Via in vitro fungicidal evaluation, the moderate to high activities of several compounds against eight phytopathogenic fungi were demonstrated. Especially, the fungicidal activities of compounds 5-03 and 5-09 were comparable to those of the controls azoxystrobin and trifloxystrobin in precise virulence measurements for four fungi. These results suggested that dihydrobenzo[e][1,2]oxazepin-4(1H)-one analogues could be considered as potential fungicidal candidates for crop protection.

Correction for ‘Design, synthesis, crystal structure and fungicidal activity of (E)-5-(methoxyimino)-3,5-dihydrobenzo[e][1,2]oxazepin-4(1H)-one analogues’ by Dongyan Yang et al., Med. Chem. Commun., 2017, 8, 1007–1014.

Palladium contamination causes potential danger to the environment, and a study of its biological safety is still on the way. Here, a fluorescent and colorimetric probe (compound 1) containing oxime-ether for Pd2+ has been developed. 1 can detect Pd2+ in aqueous samples with high selectivity and sensitivity. 1 can also work well in biological samples, which gives access to detect Pd2+ in an organism.

N′-Nitro-2-hydrocarbylidenehydrazinecarboximidamides and methoxyacrylates are two types of important agrochemicals. By combining their key fragments into one framework, a series of the title compounds was designed and synthesized. Some of these compounds have shown excellent insecticidal activities for aphides, for example, the LC50 values of compounds 6-06, 6-11 and 6-19 against M. perslcae and H. amygdale were found to be 1.9/14.4, 13.4/1.5 and 0.3/38.4 mg L−1 respectively. They were also effective against the mycelium growth of B. cinerea in vitro. Compound 6-04 could control (∼100%) cucumber anthrax and rice blast at 100 mg L−1 in vivo, and inhibit the spore germination (∼100%) of vegetable gray mold at 6.25 mg L−1. These compounds could be considered as potential insecticidal or fungicidal candidates for crop protection. The results of structure–activity relationship (SAR) studies are discussed.

A “turn-on” fluorescent and colorimetric chemosensor (RBS) for Pd2+ has been designed and synthesized through introduction of sulfur as a ligand atom to Rhodamine B. RBS exhibits high selectivity (freedom from the interference of Hg2+ in particular) and sensitivity toward Pd2+ with a detection limit as low as 2.4 nM. RBS is also a reversible sensor, and it can be made into test paper to detect Pd2+ in pure water. Compared to the chemosensors that introduced phosphorus to Rhodamine to detect Pd2+, RBS can be synthesized more simply and economically.Keywords: chemosensor; colorimetric; fluorescent; high selectivity; palladium; reversible

2′,3′-Benzoabscisic acid 4a is significantly more active than (±)-ABA and can be potentially used as a plant growth regulator for agriculture. In this study, six 4a analogs were designed and synthesized. Bioassay showed that 4a displayed greater activity than (±)-ABA and the six analogs produced less inhibition than 4a itself. Specially, some analogs displayed markedly different activities to different physiological and biochemical process, which were largely different from ABA and 4a. Compared to (±)-ABA, 4b and 4c were more effective germination inhibitors for lettuce, but less effective inhibitors for rice elongation. Five-membered analog 5 was higher or slightly weaker in inhibiting Arabidopsis seed germination and rice elongation, respectively, but at least 10 times less effective than (±)-ABA in lettuce seed germination. Dual acid 6 and alkyne acid 20 nearly produced no inhibitory activity for Arabidopsis seed germination, but displayed excellent activity in inhibiting rice seedling growth. The preference of the analogs to different physiology process indicated that they might provide a strategy to develop novel ABA agonists or antagonist and be used as probe to investigate the function of different ABA receptors.2′,3′-Benzoabscisic Acid Analogs with Excellent ABA Like Activity and Preference to Different Physiological Process.

•16 ABA esters were prepared by two different esterification routes.•Some ABA esters showed much better or nearly the same activity compared to ABA.•Chemical hydrolysis ability of the ABA esters had little relationship to their bioactivity.•Good penetration and synergistic activity might contribute to the high activities of ABA esters.16 ABA esters including 11 new compounds were prepared by two different esterification routes. All the structures of ABA esters were confirmed by 1H NMR, 13C NMR and HRMS. Their biological activity and hydrolysis stability were investigated. Fortunately, there were 15 and 9 compounds which displayed much better or nearly the same inhibition activity for rice seedling growth and Arabidopsis thaliana seed germination compared to ABA, respectively. Especially, compounds 2d and 2g showed better biological activities than ABA in the three tests. Moreover, we found that chemical hydrolysis ability of the esters in vitro had little relationship to their biological activity.

•A cis-2,3-cyclopropanated ABA analogue was designed and synthesized successfully.•Its photostability is 4-fold higher than that of (±)-ABA.•cis-2,3-cyclopropanated ABA has high ABA-like activity.The plant hormone abscisic acid (ABA) plays a central role in the regulation of plant development and adaptation to environmental stress. The isomerization of ABA to the biologically inactive 2E-isomer by light considerably limits its applications in agricultural fields. To overcome this shortcoming, an ABA analogue, cis-2,3-cyclopropanated ABA, was synthesized, and its photostability and biological activities were investigated. This compound showed high photostability under UV light exposure, which was 4-fold higher than that of (±)-ABA. cis-2,3-cyclopropanated ABA exhibited high ABA-like activity, including the ability to effectively inhibit seed germination, seedling growth and stomatal movements of Arabidopsis. In some cases, its bioactivity approaches that of (±)-ABA. trans-2,3-cyclopropanated abscisic acid was also prepared, an isomer that was more photostable but which showed weak ABA-like activity.To inhibit the isomerization of plant hormone ABA by light, a cis-2,3-cyclopropanated ABA analogue was designed and synthesized successfully. The compound has notably higher photostability compared to ABA and shows high ABA-like activity.

A novel series of acyclic imine-substituted nitenpyram analogues were designed and synthesized from nitroaminoguanidine, and their structures were confirmed using X-ray diffraction crystallography. Preliminary bioassays showed that the target molecules exhibited good activities against aphids in laboratory (Myzus persicae Sulzer) and field trials (M. persicae Sulzer and Brevicoryne brassicae Linnaeus). Comparative molecular field analysis and comparative molecular similarity indices analysis were employed to develop a three-dimensional quantitative structure–activity relationship model that describes the insecticidal activity of 21 neonicotinoid derivatives. Simple synthesis, low cost, and good insecticidal activity have made this series of compounds become very promising candidates for future commercial pesticides.

The effects of a novel fungicide, pyrimorph, on the soil enzyme activities and respiration in upland soil were studied over a period of 90 days. Pyrimorph ranged from 0.5 to 150 mg kg−1 accelerated the activities of catalase, invertase and dehydrogenase in soil. Urease activities in soil treated with 50–150 mg kg−1 pyrimorph were also stimulated significantly within the first 45 days, but inhibited obviously from 60 to 90th day of incubation. Among the four enzymes, dehydrogenase was most sensitive to pyrimorph, and the highest activities in samples treated by pyrimorph with 100 or 150 mg kg−1 were 5-and 5.3-fold to that of the control, respectively. Soil respiration was stimulated within the first 14 days, and then from the 21th day, there were no distinct difference between the treated samples and the control. All the results demonstrated that pyrimorph at the lowest dose (0.5 mg kg−1) would not exhibited any toxicological threat to soil enzymes and soil respiration. Moreover, higher concentrations in a range 5–150 mg kg−1 displayed an activation effect on soil enzymes and soil respiration, yet a certain potential threat to soil urease in the last stage of incubation.Highlights► Pyrimorph accelerated the activities of soil catalase, invertase and dehydrogenase. ► Pyrimorph had potential threat to soil urease in the last stage of incubation. ► Pyrimorph had the highest positive effect on dehydrogenase. ► Pyrimorph increased soil respiration within the first 14 days. ► The main effects of pyrimorph on soil enzymes and soil respiration were positive.

A series of 1,1-diaryl tertiary alcohols and some of their dehydration derivatives were designed, synthesized and evaluated for their antifungal activities. Some compounds exhibited moderate inhibitory activities against seven plant pathogens at 50 μg/mL in vitro, compounds 5g and 7c displayed nearly the same or higher fungicidal activities against some certain plant pathogens compared with the lead compound pyrimorph. A qualitative structure-activity relationship (SAR) analysis revealed that the Cl substituent and its position at the pyridine ring were crucial for the compounds’ activities. Specially, several compounds displayed 100% protection effect against wheat powdery mildew or cucumber anthrax at 400 mg/mL in vivo, which suggested that these compounds might be potential fungicidal candidates for certain plant diseases.